Handheld mobile devices, such as smart phones and cellular phones, are typically enclosed in hard cases composed of hard materials that present a low-friction surface. This type of enclosure provides impact resistance and durability; however, such smooth-surfaced, low-friction materials have some drawbacks. For example, a mobile device with a hard, slippery, plastic case will readily slide across most surfaces, such as a car dashboard or seat. This can cause the mobile device to fall out of reach, and it can be especially dangerous to retrieve while driving. Furthermore, a slippery surface can contribute to the mobile device being dropped and broken.
Rubber surfaces have been used to partially cover mobile devices. However, the high-friction properties of rubber enclosures that provide a superior gripping feature also greatly inhibit the ability of the user to put the device in a holster, since the high-friction rubber resists being inserted and removed from the holster.